One of the free software projects we have been talking to as of late about better enhancing their benchmarking capabilities for likely integration into the Phoronix Test Suite is Rigs of Rods. While the graphics within this driving simulator may not be the best (at least when compared to Unigine, or within the open-source world, Nexuiz) it's not the graphics that the developers pride themselves on but rather the physics capabilities. Rigs of Rods began as a truck driving simulator game, but since then has turned into a rather interesting physics sandbox of goodies. A new release of their code-base was just made.